'ER' star to undergo surgery for tumour

Former ER star Maura Tierney has announced that she will undergo surgery to remove a breast tumour.

The actress, who played Abby Lockhart in the long-running medical drama, confirmed the news after NBC revealed that filming on her new series Parenthood had been postponed because of her health, People reports.

"I have discovered a tumour in my breast which requires surgery. I will not know either my exact diagnosis or course of treatment until that surgery is performed," she said.

"My doctors have all assured me this is a very treatable condition. I'm very optimistic as to the outcome and want to thank everyone who has sent positive thoughts and support. I look forward to going back to work soon."

The 44-year-old had been scheduled to begin filming Parenthood on July 27, but medical drama Mercy will now take over its slot.